1. Field of the Invention
The present invention relates to an image processing method and image processing device for carrying out image processing on the basis of image data and drawing instructions.
2. Description of the Related Art
Desktop publishing (DTP) creates a page layout by implementation of image creation, processing, editing, etc. on a processing device such as a personal computer, a workstation or the like. On the basis of this page layout, a film for exposure of a printing plate is created (CEPS), the printing plate is directly written therefrom, and a plate for production printing is created (CTP: Computer-To-Plate)).
In DTP, when proofreading is to be carried out before actually creating a printing plate or production printing using a printing plate, WYSIWYG functions may be utilized to print out a page layout that is displayed on a monitor from a color printing device, such as a laser printer or the like.
In usual color printing, four colors are employed as process colors: cyan (C), magenta (M), yellow (Y) and black (K). Printing is sometimes implemented by using a single color selected from the process colors (single-color printing), or two of the process colors (two-color printing) or three of the process colors (three-color printing). Further, printing that employs a “spot colors” in place of a process color is sometimes implemented. Further still, with a view to lowering printing costs and the like, two-color printing is sometimes implemented using, for example, two spot colors or one spot color and one process color.
Generally, in a DTP application, color mixing of process colors is simple. However, when printout data (a page layout) is to be created for two-color printing, in many applications it is not possible to instruct color-mixing of spot colors. Accordingly, when a DTP application is used to create a page layout for two-color printing using (a) spot color(s), it is common for the page layout to be created and printed on film using two process colors.
However, if a process color is used instead of a spot color when a page layout is created for two-color printing using spot colors, when a laser printer or the like is to be employed to print out this page layout for comprehension or proofing, the page layout is printed by two-color printing using process colors. Thus, it is difficult to obtain an accurate printing simulation of how the final printed matter will appear.
Accordingly, a method has been proposed in which a special profile is created beforehand and it is possible to simulate two-color printing using spot colors with this profile.
Meanwhile, in printing using actual printing inks (printing of a final product), color of a paper may differ from when a printing simulation was performed. As a result, printed matter obtained in the printing simulation and the actual product of printing may differ in their finished appearances.
That is, it is often the case that paper with a color close to white is used in a printing simulation, but the paper used in actual printing may have various colors and the final product is often printed on paper with a color other than white.
Therefore, when two-color printing or three-color printing is to be implemented, a printing simulation must include the color of the paper that will be used when the final product is obtained.
When full-color printing is to be implemented, a paper color can be simulated by color correction. However, in two-color printing and the like, particularly when a spot color is included, it is difficult to simulate a paper color by color correction.
Accordingly, methods of using special profiles which are matched to paper colors have been considered. However, in such a case, each time the color of paper changes, it is necessary to create a profile to suit the new paper color. Resultantly, great volumes of work, time and expense are incurred. Furthermore, when a method of performing a simulation of two-color printing or the like simply from the name of a spot color is employed, it is necessary to create a special CMYK profile to match the color of a paper.